Amplify workbook pages 26-28?

Yes, endothermic means it turns cold. and some chemical changes include change of tempature.

D. h2o + h2o > h3o + oh- confirmed.

It is a ok  i know i have a brain functioning well.                                                                                                                                                           

Answer is: value of q is 5·10⁻⁶m.chemical reaction: mg²⁺(aq) + co₃²⁻(aq) → mgco₃(s).c(mg²⁺) = 2.5·10⁻³ m; concentration of magnesium cations.c(co₃²⁻) = 2.00·10⁻³ m; concentration of carbonate anions.q = c(mg²⁺)  · c(co₃²⁻).q = 2.5·10⁻³ m  · 2.00·10⁻³ m.q = 5·10⁻⁶m.q = 0.000005 m.